Bug 1073952: inherit CSP into iframe sandbox srcdoc r=ckerschb,dveditz

MozReview-Commit-ID: KTzCLoDfYnd

caps/BasePrincipal.cpp

@@ -433,6 +433,21 @@ BasePrincipal::GetCsp(nsIContentSecurityPolicy** aCsp)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+BasePrincipal::SetCsp(nsIContentSecurityPolicy* aCsp)
+{
+  // Never destroy an existing CSP on the principal.
+  // This method should only be called in rare cases.
+
+  MOZ_ASSERT(!mCSP, "do not destroy an existing CSP");
+  if (mCSP) {
+    return NS_ERROR_ALREADY_INITIALIZED;
+  }
+
+  mCSP = aCsp;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 BasePrincipal::EnsureCSP(nsIDOMDocument* aDocument,
                          nsIContentSecurityPolicy** aCSP)

caps/BasePrincipal.h

@@ -212,6 +212,7 @@ public:
   NS_IMETHOD SubsumesConsideringDomain(nsIPrincipal* other, bool* _retval) final;
   NS_IMETHOD CheckMayLoad(nsIURI* uri, bool report, bool allowIfInheritsPrincipal) final;
   NS_IMETHOD GetCsp(nsIContentSecurityPolicy** aCsp) override;
+  NS_IMETHOD SetCsp(nsIContentSecurityPolicy* aCsp) override;
   NS_IMETHOD EnsureCSP(nsIDOMDocument* aDocument, nsIContentSecurityPolicy** aCSP) override;
   NS_IMETHOD GetPreloadCsp(nsIContentSecurityPolicy** aPreloadCSP) override;
   NS_IMETHOD EnsurePreloadCSP(nsIDOMDocument* aDocument, nsIContentSecurityPolicy** aCSP) override;

caps/nsIPrincipal.idl

@@ -137,10 +137,11 @@ interface nsIPrincipal : nsISerializable
 
     /**
      * A Content Security Policy associated with this principal.
-     *
      * Use this function to query the associated CSP with this principal.
+     * Please *only* use this function to *set* a CSP when you know exactly what you are doing.
+     * Most likely you want to call ensureCSP instead of setCSP.
      */
-    [noscript] readonly attribute nsIContentSecurityPolicy csp;
+    [noscript] attribute nsIContentSecurityPolicy csp;
 
     /*
      * Use this function to query a CSP associated with this principal.

caps/nsNullPrincipal.cpp

@@ -106,6 +106,20 @@ nsNullPrincipal::GetHashValue(uint32_t *aResult)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsNullPrincipal::SetCsp(nsIContentSecurityPolicy* aCsp) {
+  // Never destroy an existing CSP on the principal.
+  // This method should only be called in rare cases.
+
+  MOZ_ASSERT(!mCSP, "do not destroy an existing CSP");
+  if (mCSP) {
+    return NS_ERROR_ALREADY_INITIALIZED;
+  }
+
+  mCSP = aCsp;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsNullPrincipal::GetURI(nsIURI** aURI)
 {
@@ -187,4 +201,3 @@ nsNullPrincipal::Write(nsIObjectOutputStream* aStream)
 
   return NS_OK;
 }
-

caps/nsNullPrincipal.h

@@ -42,6 +42,7 @@ public:
 
   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
   NS_IMETHOD GetHashValue(uint32_t* aHashValue) override;
+  NS_IMETHOD SetCsp(nsIContentSecurityPolicy* aCsp) override;
   NS_IMETHOD GetURI(nsIURI** aURI) override;
   NS_IMETHOD GetDomain(nsIURI** aDomain) override;
   NS_IMETHOD SetDomain(nsIURI* aDomain) override;

caps/nsScriptSecurityManager.cpp

@@ -303,6 +303,30 @@ nsScriptSecurityManager::GetChannelResultPrincipal(nsIChannel* aChannel,
               attrs.StripAttributes(OriginAttributes::STRIP_ADDON_ID);
               prin = nsNullPrincipal::Create(attrs);
             }
+            // if the new NullPrincipal (above) loads an iframe[srcdoc], we
+            // need to inherit an existing CSP to avoid bypasses (bug 1073952).
+            // We continue inheriting for nested frames with e.g., data: URLs.
+            if (loadInfo->GetExternalContentPolicyType() == nsIContentPolicy::TYPE_SUBDOCUMENT) {
+              nsCOMPtr<nsIURI> uri;
+              aChannel->GetURI(getter_AddRefs(uri));
+              nsAutoCString URISpec;
+              uri->GetSpec(URISpec);
+              bool isData = (NS_SUCCEEDED(uri->SchemeIs("data", &isData)) && isData);
+              if (URISpec.EqualsLiteral("about:srcdoc") || isData) {
+                nsCOMPtr<nsIPrincipal> principalToInherit = loadInfo->PrincipalToInherit();
+                if (!principalToInherit) {
+                  principalToInherit = loadInfo->TriggeringPrincipal();
+                }
+                nsCOMPtr<nsIContentSecurityPolicy> originalCsp;
+                principalToInherit->GetCsp(getter_AddRefs(originalCsp));
+                // if the principalToInherit had a CSP,
+                // add it to the newly created NullPrincipal.
+                if (originalCsp) {
+                  nsresult rv = prin->SetCsp(originalCsp);
+                  NS_ENSURE_SUCCESS(rv, rv);
+                }
+              }
+            }
             prin.forget(aPrincipal);
             return NS_OK;
         }
@@ -335,7 +359,7 @@ nsScriptSecurityManager::GetChannelResultPrincipal(nsIChannel* aChannel,
 
             nsCOMPtr<nsIURI> uri;
             nsresult rv = NS_GetFinalChannelURI(aChannel, getter_AddRefs(uri));
-            NS_ENSURE_SUCCESS(rv, rv); 
+            NS_ENSURE_SUCCESS(rv, rv);
             nsCOMPtr<nsIPrincipal> principalToInherit = loadInfo->PrincipalToInherit();
             if (!principalToInherit) {
               principalToInherit = loadInfo->TriggeringPrincipal();

caps/nsSystemPrincipal.cpp

@@ -49,7 +49,7 @@ nsSystemPrincipal::GetHashValue(uint32_t *result)
     return NS_OK;
 }
 
-NS_IMETHODIMP 
+NS_IMETHODIMP
 nsSystemPrincipal::GetURI(nsIURI** aURI)
 {
     *aURI = nullptr;
@@ -70,6 +70,15 @@ nsSystemPrincipal::GetCsp(nsIContentSecurityPolicy** aCsp)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsSystemPrincipal::SetCsp(nsIContentSecurityPolicy* aCsp)
+{
+  // Never destroy an existing CSP on the principal.
+  // This method should only be called in rare cases.
+
+  return NS_ERROR_FAILURE;
+}
+
 NS_IMETHODIMP
 nsSystemPrincipal::EnsureCSP(nsIDOMDocument* aDocument,
                              nsIContentSecurityPolicy** aCSP)

caps/nsSystemPrincipal.h

@@ -30,6 +30,7 @@ public:
   NS_IMETHOD GetDomain(nsIURI** aDomain) override;
   NS_IMETHOD SetDomain(nsIURI* aDomain) override;
   NS_IMETHOD GetCsp(nsIContentSecurityPolicy** aCsp) override;
+  NS_IMETHOD SetCsp(nsIContentSecurityPolicy* aCsp) override;
   NS_IMETHOD EnsureCSP(nsIDOMDocument* aDocument, nsIContentSecurityPolicy** aCSP) override;
   NS_IMETHOD GetPreloadCsp(nsIContentSecurityPolicy** aPreloadCSP) override;
   NS_IMETHOD EnsurePreloadCSP(nsIDOMDocument* aDocument, nsIContentSecurityPolicy** aCSP) override;

dom/security/test/csp/file_iframe_sandbox_srcdoc.html

@@ -0,0 +1,11 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Bug 1073952 - CSP should restrict scripts in srcdoc iframe even if sandboxed</title>
+</head>
+<body>
+<iframe srcdoc="<img src=x onerror='parent.postMessage({result: `unexpected-csp-violation`}, `*`);'>"
+        sandbox="allow-scripts"></iframe>
+</body>
+</html>

dom/security/test/csp/file_iframe_sandbox_srcdoc.html^headers^

@@ -0,0 +1 @@
+content-security-policy: default-src *;

dom/security/test/csp/mochitest.ini

@@ -203,6 +203,8 @@ support-files =
   file_strict_dynamic_default_src.html
   file_strict_dynamic_default_src.js
   file_upgrade_insecure_navigation.sjs
+  file_iframe_sandbox_srcdoc.html
+  file_iframe_sandbox_srcdoc.html^headers^
 
 [test_base-uri.html]
 [test_blob_data_schemes.html]
@@ -290,3 +292,4 @@ tags = mcb
 [test_strict_dynamic_parser_inserted.html]
 [test_strict_dynamic_default_src.html]
 [test_upgrade_insecure_navigation.html]
+[test_iframe_sandbox_srcdoc.html]

dom/security/test/csp/test_iframe_sandbox_srcdoc.html

@@ -0,0 +1,62 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Bug 1073952 - CSP should restrict scripts in srcdoc iframe even if sandboxed</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<p id="display">Bug 1073952</p>
+<iframe style="width:200px;height:200px;" id='cspframe'></iframe>
+<script class="testbody" type="text/javascript">
+
+// This is used to watch the blocked data bounce off CSP and allowed data
+// get sent out to the wire.
+function examiner() {
+  SpecialPowers.addObserver(this, "csp-on-violate-policy", false);
+}
+
+examiner.prototype  = {
+  observe: function(subject, topic, data) {
+
+    if(topic === "csp-on-violate-policy") {
+      var violationString = SpecialPowers.getPrivilegedProps(SpecialPowers.
+                             do_QueryInterface(subject, "nsISupportsCString"), "data");
+      // the violation subject for inline script violations is unfortunately vague,
+      // all we can do is match the string.
+      if (!violationString.includes("Inline Script")) {
+        return
+      }
+      ok(true, "CSP inherited into sandboxed srcdoc iframe, script blocked.");
+      window.finish();
+    }
+  },
+
+  // must eventually call this to remove the listener,
+  // or mochitests might get borked.
+  remove: function() {
+    SpecialPowers.removeObserver(this, "csp-on-violate-policy");
+  }
+}
+
+window.examiner = new examiner();
+
+function finish() {
+  window.examiner.remove();
+  SimpleTest.finish();
+}
+
+addEventListener("message", function(e) {
+  ok(false, "We should not execute JS in srcdoc iframe.");
+  window.finish();
+})
+SimpleTest.waitForExplicitFinish();
+
+// save this for last so that our listeners are registered.
+// ... this loads the testbed of good and bad requests.
+document.getElementById('cspframe').src = 'file_iframe_sandbox_srcdoc.html';
+
+</script>
+</body>
+</html>